The most common and most likely answer to this crossword clue is the 7 letter word PONTOON
I've seen this crossword clue in The Guardian
P
O
N
T
O
O
N
More clues leading to the result PONTOON
Buddy explains!

The straight part
We know that "Bridge/card game" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bridge/card game = pontoon.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PONTOON mean?
PONTOON noun- A flat-bottomed boat used as a support for a temporary bridge.
- A floating structure supporting a bridge or dock.
- A box used to raise a sunken vessel.
- A float of a seaplane.
- A lighter or barge used for loading or unloading ships.
- A card game in which the object is to obtain cards whose value adds up to, or nearly to, 21 but not exceed it.